Relevant prior art hydrofoil devices include the “Trampofoil” device disclosed in Swedish Design Patent no. 98-0088 and a Water Vehicle disclosed in U.S. Pat. No. 6,099,369 issued to Puzey.
The Trampofoil discloses a basic self-propelled hydrofoil device having a main foil in the rear and a steerable foil in the front. The '369 patent issued to Puzey discloses a related device that has a biased pivot point located substantially above the rear foil, i.e., under the area at which a user stands when in use (FIG. 9, item 82, or FIG. 10, item 72).
Disadvantageous aspects of the Trampofoil device and the '369 patent include that they are inefficient in their transfer of the user generated driving force to drive the foil. This inefficiency in turn renders them relatively exhausting to use and the experience short lived. The Trampofoil and '369 device have a drive foil that is biased into the “coast” position. To move it into a drive position, a user must jump onto the user platform and thrust downward. A large portion of this thrust does not go to driving the foil but rather to reorienting the foil from the coast to the drive position. Once reoriented, the remaining thrust force may go to driving the foil.
A need thus exists for a self-propelled hydrofoil device in which the drive foil may be placed in the appropriate drive position prior to a user thrust so that the energy of the user thrust is more efficiently used for driving the hydrofoil device forward. A need also exists for a hydrofoil device that affords a user greater control over foil position, leverage to assert that control and a simplicity of design that decreases costs while not impacting (and potentially improving) performance.